1. Field of the Invention
The present invention relates to a processing technique for determining the presence/absence of a printing failure in a printing apparatus which prints image data on a predetermined medium on which image data is printed.
2. Description of the Related Art
Conventionally, in the commercial printing industry, a printed product is issued through various work processes. The work processes include, for example, document entry, layout editing, proofreading (layout correction and color correction), proof printing, block copy preparation, printing, post process, checking, and shipping.
Especially, since an offset printing press is mainly used in printing in the commercial printing industry, it is essential to prepare a block copy. However, once the block copy is prepared, it is difficult and costly to correct the block copy. Thus, careful proofreading (i.e., careful layout check and color confirmation) is indispensable for preparing the block copy. Accordingly, a predetermined period of time is generally taken to completely issue the printed product.
In such a situation, higher-speed and higher-image quality electrophotographic and inkjet printing apparatuses have been introduced. A market called print-on-demand (to be referred to as a POD hereinafter) has appeared in competition with against the commercial printing industry.
POD has appeared in place of the above-mentioned large-scale printing apparatus or printing scheme such that a relatively small-lot job can be handled in a short delivery period without using the large-scale apparatus or system.
In the POD market, digital printing using electronic data can be implemented to provide a printing service by making the best of digital image forming apparatuses such as a digital copying machine and digital multi-function peripheral.
However, in the above-described commercial printing industry or POD market, it is not automatically checked whether there is a printing failure on a printed product to be delivered to a customer. Under the present conditions, an operator manually checks the printed product. When the printed product has several hundred pages, it takes a very long time and many processes to check the printed product in detail for each page. Hence, the checking accuracy becomes rough in practice, and small printing errors, omissions, and dirt on a sheet of paper are not detected, thus posing a problem.
Under these circumstances, a technique of automatically checking the printed product is demanded. Note that a technique of checking a printed product by comparing a verification image for verifying the printed product with an image obtained by sensing the printed product is known as a technique of automatically checking the printed product (see, e.g., Japanese Patent Application Laid-Open No. 11-39492).
However, a conventional checking technique does not consider processing content to be executed for a printed product after printing. For example, in checking a printed product, an entire printed medium need not always be checked. More specifically, when a part of the medium is not used after the printing and cutting processes, this unnecessary portion need not to be checked. If the entire medium is checked even in such a case, it takes a long time and requires a heavy process load to check the medium. Additionally, since a target (area) to be checked becomes large, the checking accuracy may decline.